In the manufacture of a sheet metal workpiece into a finished product the workpiece may be moved successively through a plurality of stations at each of which the workpiece may or may not be subjected to an operation. Apparatus of this kind typically is incorporated in progressive die stamping machinery having a plurality of stations arranged along a common longitudinal axis.
One example of a progressive die stamping press is disclosed in U.S. Pat. No. 4,887,446 issued Dec. 19, 1989. The workpiece transfer apparatus is adjacent, but separate from, the die stations of the stamping press. Elongate rails are positioned on opposite sides of the die stations and are controlled by actuators. Extending inwardly from the rails, i.e., toward the die stations, is a plurality of transfer arms arranged in sets of four for each die station. The transfer arms are adapted to engage a workpiece on opposite sides thereof and each transfer arm has a support at its distal end for engaging and supporting the workpiece.
A disadvantage of known transfer arms is that they are not adjustable to accommodate workpieces of different size or shape. As a consequence, when the machinery is adjusted to accommodate workpieces of different size or shape, the transfer arms used with one size and shape workpiece must be replaced with arms capable of accommodating a different size or shaped workpiece. The necessity of replacing one set of transfer arms with another is a time consuming and expensive undertaking.